Various types of aquatic sports boards, including body boards, surf boards, kickboards, and windsurfer boards, are known to the prior art. Such devices typically consist of a foam core covered with a surface layer. U.S. Pat. No. 3,929,549 (Smith), U.S. Pat. No. 3,802,010 (Smith), U.S. Pat. No. 4,836,814 (McDonald et al.), and U.S. Pat. No. 4,129,911 (McDonald et al.), for example, disclose aquatic boards made with a foam interior and a hardened fiberglass exterior. Other references show boards in which the foam core is provided with a skin made out of polyethylene film or foam.
It is known to decorate the skin of an aquatic board with graphics and other designs, as exemplified by U.S. Pat. No. 5,211,593 (Schneider et al.). It is also known to modify the top surface of an aquatic board with ridges, dimples and the like to improve the aesthetic appeal of the board, as in U.S. Pat. No. 5,114,370 (Moran) and U.S. Pat. No. 4,752,260 (Stewart), or to provide contours in the upper surface to improve the user's grip, as in U.S. Pat. No. 5,116,269 (Moran).
To date, various designs have been proposed for the rails on aquatic boards. The rail is the edge or side of the board which is used to control the lateral movement of the board as it passes through the water. The rail may be an integral part of the core of the board, or it may be in the form of a distinct strip or portion that is attached to the side of the board.
In some proposed designs for aquatic boards, the rails protrude outwardly. Des. 345,000 (Foulke), Des. 315,770 (Shanelec) and Des. 194,646 (Del Mar) are exemplary. The shape of these rails has the effect of increasing the surface area of the rail in contact with the water, thereby increasing the holding power of the bodyboard in the water. While this effect is desirable for certain applications, however, the increased drag attendant with such rails slows the passage of the aquatic board through the water.
Some attempts have been made to reduce the drag of an aquatic board as it passes through the water, thereby increasing its speed. One such effort has been aimed at effecting changes in the angle between the rail and the bottom of the board. Thus, U.S. Pat. No. 4,752,260 (Stewart) and U.S. Pat. No. 4,571,195 (Brooks, Jr.) disclose body boards wherein a step is provided on the rail. This step is an area of the rail that is substantially perpendicular to the bottom of the bodyboard. According to U.S. Pat. No. 4,752,260 (Stewart), water traveling along the hull shears off of the hull and away from the step, thereby decreasing the resistance of the bodyboard as it passes through the water and increasing its speed.
However, in practice, it has been found that aquatic boards of the type shown in U.S. Pat. No. 4,752,260 (Stewart) and U.S. Pat. No. 4,571,195 (Brooks, Jr.) still possess an amount of drag that is unacceptable for some applications. Furthermore, introduction of the step in these boards sacrifices some of the handling features enjoyed by rail profiles that are not stepped. There is thus a need for a method of reducing the drag on an aquatic board without changing the overall rail profile.
U.S. Pat. No. 4,395,241 (Comparetto) discloses an amphibious sled equipped with a perforated water catcher. The "water catcher" is a flexible sheet which is attached to each side of the front of the sled and is wrapped inwardly onto the deck of the sled during use to form a venturi. The perforations on the water catcher serve to reduce drag or wave turbulence.
However, the use of a water catcher is inconvenient for most aquatic boards, since its use is limited primarily to the surf, and since it interferes with the rail profile. Furthermore, water catchers require skillful manipulation by the user to attain desirable results, and do not improve the speed generated by the rails of an aquatic device. Also, since water catchers operate by forming a venturi which allows the device to which they are attached to be pulled by a wave, they do not improve the speed of an aquatic board while it is being pushed by a wave, and in fact reduce the speed generated by the rails of an aquatic device by increasing the overall surface area at the front of the board.
Surprisingly, it has been found that the speed of an aquatic board can be increased by introducing one or more apertures into the rails of the board. Without being bound by any particular scientific theory, it appears that the apertures reduce the surface area of the rail that is exposed to the water, thus reducing the drag.